This invention pertains to an imaging sensor, and more particularly to an imaging sensor having defects.
Complementary Metal Oxide Semiconductor (CMOS) sensors are an alternative to Charge Coupled Devices (CCDs) in imaging devices. Unlike a CCD, the individual picture elements (pixels) in the CMOS sensor are separately addressable. This gives CMOS sensors an advantage over CCDs: a defective pixel does not make the entire CMOS sensor unusable. Today, CMOS sensors are used in all manners of imaging devices: for example, digital still and video cameras, optical scanners, facsimile machines, and robotics, to name just a few.
But detecting defects is an expensive process, employing special equipment and test patterns to identify defective pixels in the CMOS sensor. This testing is done after production of the CMOS sensor to determine if the defects make the CMOS sensor unusable. An imaging device utilizing a CMOS sensor may compensate for a few defective pixels by interpolating from neighboring pixels. But too many defects clustered together may result in the CMOS sensor to be discarded.
Once the CMOS sensor passes testing, the results of the testing are discarded. Imaging device manufacturers then retest the CMOS sensor to determine which pixels are defective and xe2x80x9ccompensated.xe2x80x9d Because CMOS sensor testing is expensive and complicated, few facilities have the capability to do the testing. Further, if the imaging device is damaged, it is generally cheaper to replace the imaging device than to re-test the CMOS sensor after the imaging device has been repaired.
The present invention addresses at least in part these and other problems associated with the prior art.